1. Field of the Invention
This invention relates to a washing process which is particularly suitable for institutional laundries and which is based on the development of a new, paste-form detergent composition which is fed into the washing process by means of a dosing system designed specifically for this detergent.
2. Discussion of Related Art
There are many know liquid to paste-form detergents. They are generally designed to meet domestic requirements, i.e., are intended to be sufficiently liquid so that they may be poured out and dispensed without difficulty. Since, in addition, they are required to be stable in storage over a relatively wide temperature range, it is normally necessary that they contain organic solvents and/or hydrotropic additives. However, such additives are inactive in the washing process, are comparatively expensive and also occupy packaging volume, storage and transport capacity. Above all, the presence of inflammable solvents is problematical, necessitating additional safety precautions on account of the comparatively high throughput of detergents in laundries. Accordingly, detergent concentrates of the type mentioned are suitable to only a limited extent, if at all, for laundries.
Because of this, powder-form detergents are mainly used in laundries. Since the exact dosing of detergents such as these is problematical of laborious, particularly in large, substantially automated laundries, the detergents are mostly stored and dosed or dispensed in predissolved form as stock liquors, i.e., an aqueous concentrate is prepared and then fed to the individual points of use. However, the detergents normally used in laundries contain comparatively large amounts of washing alkalis which possess only limited solubility in cold water and, in addition, produce salting-out effects. They cause phase separation with the result that the organic components, particularly the nonionic surfactants and soaps, separate and cream up. Accordingly, relatively high dilution in water is necessary, in addition to which the stock liquors have to be continuously intensively mixed and circulated to prevent individual components from settling in the feed lines to the points of use. Accordingly, processes of the type herein involve heavy expenditure for large mixing vessels and the associated controls and for mixers and feeders and also a constant power supply for thermostatic control and pumping of the stock liquors.
Accordingly, there is a considerable need for detergent compositions and corresponding dosing systems by which the problems mentioned above are avoided and which satisfy the following requirements: high detergency; absence of washing-inactive additives which merely serve to condition the detergent; minimal occupation of packaging, transport and storage volume; ready processibility, even at low temperatures (super-cooled pastes); simple connection to the dosing system with no spilling; simple and compact dosing system; suitability of the dosing system for fully automatic process control; wide variability in regard to the choice of the quantity and concentration of detergent; immunity to problems caused by phase separation and sedimentation in containers and pipes; and minimal energy demand.
These requirements are met by the present invention.